FIG. 1A shows a schematic symbol of an SCR device 100, which acts like a diode with a control gate. As shown in FIG. 1B, SCR 100 has four layers of alternating N-type and P-type material, which are implemented as a pair of tightly coupled bipolar junction transistors (BJTs) 102A, 102B. In such an SCR device 100, when a gate current or gate-to-cathode voltage exceeds a certain threshold (e.g., when an electrostatic discharge (ESD) event occurs), SCR 100 turns “on”. SCR 114 will remain “on” even after gate current is removed so long as current/voltage through SCR 100 remains above a holding current/voltage. Once current/voltage falls below the holding current/voltage for an appropriate period of time (e.g., once an ESD event has passed), SCR 100 will switch “off” and normal blocking operation will resume.